Automatic control device



Oct. 27, 1953 sEscocc 2,657,291

AUTOMATIC CONTROL DEVICE Filed Oct. 18, 1950 INVENTOR; L (//6 fi-SCOC'CA Patented Oct. 27, 1953 UNITED STATES PATENT OFFICE AUTOMATIC CONTROL DEVICE Luis Bescocca, Florida, Buenos Aires, Argentina Application October 18, 1950, Serial No. 190,723

3 Claims.

The present invention relates to an automatic control device in which use is made of the change in physical condition produced in one or more elements to permit the operative movement of the device in controlling the operation of an electric circuit breaker, a pneumatic or hydraulic control valve, for use in safety devices, signalling apparatus etc.

The automatic controlling device in accordance with the invention includes an operative member, normally retained against movement into operative position by a trigger member. The operative member is associated with means tending to move said member in a predetermined direction and it is held in operative position by a trigger member. The trigger member is under control of two pressure means adapted to apply forces in opposite directions. One or both of these pressure means include ex pansible means responsive to a predetermined physical condition, whereby the said trigger member is automatically moved out of its operative position. Thus the operative member is permitted to escape and perform the operation in said predetermined direction.

The invention will be better understood with reference to the attached drawings in which all numbers refer to identical parts and in which Fig. 1 is a diagram of the basic principle involved in this invention showing the essential elements.

Fig. 2 is a longitudinal section taken along line 22 of Fig. 3 through the centre of one embodiment showing a circuit cut-out or safety plug, as used in domestic installations.

Fig. 3 is a plan view from above of the circuit cut-out shown in Fig. 2, with centre-pin and cover removed.

As will be evident from Figs. 1 and 2, the operative member I is held in the normal operative position by the trigger member 3, which is retained in position by the opposing forces of two means acting in the direction of the arrow 1. Whilst force 2A urges the operative member I in the predetermined direction it is restrained by the retentive action of the said trigger member 3, engaged in the slot H3.

The force 2A can be derived from spring means 2, electromagnetic or fluid pressure, or any other suitable means. It normally tends to urge the operative member I into operative action. The means 4A applying force in opposition to the force applied by means 1 tends to pull the trigger member 3 from its operative position in the slot l B thereby releasing the operative member I.

The force indicated by the arrow 1 may also be considered as a frictional resistance, or static force, which results from, forces 5A and 6A and the coefficient of friction originated as in Fig. 2 by the automatic controlling member 25 which tends to hold the trigger member 3 in the manner of a clamp or jaw, by the action of a tensor, spring, or any other suitable means.

Whenever the intensity of the force 4A surpasses that of force I, as the result of some physical condition, or whenever there is a diminution of the intensity of force I, the trigger member 3 is immediately released, is moved in the direction of the force 4A thereby allowing the operative member to escape and move in the said predetermined direction.

The embodiment of this invention shown in Fig. 2, includes a body 8 of dielectrical material which is similar in form to conventional fuse plugs and substantially cylindrical. End 8A of the body 8 is externally reduced to provide a concentric step that may be either smooth or threaded, in order to receive a cap or closure member 9. The opposite end it of the body 8 is also of reduced diameter and is provided with a portion H of still further reduced diameter. The end of body 8 which includes the projecting portion H is provided with a central opening [2 which communicates with the chamber it formed within the body 8.

A concentric groove or step [3A, is provided on the outer surface of the part I l for a purpose that will be explained below.

The chamber i3 is widened at the upper end. The body 8 is provided with a transverse aperture M which communicates with a groove or channel that opens into the interior of the body 8 adjacent a step having a planar upper surface formed in the body 8. A metallic S-shaped member is disposed in the body and in the transverse channel M and is soldered at it to an ex ternally and internally threaded metallic ferrule I i which is secured to the body portion by engagement with external threads provided on the body 8.

The small arm I5 of the plate 23 which, through its welded connection it with the ferrule ll constitutes an external electrical contact, rests upon the upper planar surface of the step in the body 8.

The opening l2 in the bottom of the body 8 is closed by a circular plate ill provided with a threaded aperture holding a flat-headed screw 19. Plate I8 is circumferentially beaded and its edges engage the above mentioned concentric groove or step I3A.

The fixed element of the retaining means or clamp includes a metal plate 6 having at least three lugs 6B extending at right angles to said plate which rests upon the upper planar edge of the body 8. The lugs EB are wedged against the walls of the chamber I3.

Plate 6 is provided with an aperture through which extends a member 28 from a wire or a thin rod 25 which member projects through an aperture in the trigger member 3 and through another aperture in the movable clamping member 5 against which member 2B is held by means of a nut 24. The clamp members 5 and 6 are normally spaced apart a distance sufficient to permit the positioning of the trigger plate 3 there'between.

The opposite end of the wire or rod 25 is provided with a loop which is fitted around the stem of the screw I!) which holds it firmly against the plate I8. Thus an electric circuit is completed between plate It and ferrule Ii, through screw I9 rod or wire 25 nut 27, flexible conductor wire or rod 32, forked switch jaws 25 at the lower end of the operative member I and the S-shaped member 23 soldered at if: to the ferrule IT.

The screw I9 can hold the wire or rod 25 in position either by screwing it into a threaded aperture in the stem of the screw or by a simple loop surrounding the stem as shown.

The opposite extremity of the rod or wire 25 is adapted to make contact with the outer surface of the movable clamping member 5. It passes through the lower fixed plate 8 and the trigger member 3 without touching either of them and has a threaded end member 28 engaged by a nut 24 for adjusting the tension of the wire or red 25 to control the clamping or friction factor of the members 5 and 5 upon the trigger member 3 to the exact degree required.

Member 28 may be of a semicircular cross section to fit loosely into a suitably shaped aperture in the lower fixed clamp member 6. Below the nut 24 a washer having a corresponding semicircular aperture may be provided so that member 28 and the wire or red 25 will not be able to rotate when the nut 24 is turned.

The clamping pressure, therefore, is regulated by utilizing the nut 2d as an adjusting element.

The lid 9 can be made of dielectric material. It may be provided with an internal thread matching the thread around the body 8 or it may be merely a tight fitting push on cap, with or without bayonet slot side fittings.

The lid 9 is provided with a central aperture for the stem or rod 5 of the operative or escape member.

The outer extremity of the operative member I is provided with a knob or button 2! of dielectric material. The stem of this member may be a metal tube or rod, or it may be of dielectric material and provided with a longitudinal slot 26. A lateral slot IB is provided in a predetermined position, into which the trigger member 3 fits when in the closed circuit, stationary position. The stem of the operative member I which carries the forked switch jaws 26A, attached by means of the screw 28, may be a solid rod of any suitable material, or, as in the embodiment illustrated in Fig. 2, may consist of a tube I slidingly held in a shorter tube EC a pin 30 which is firmly secured in the outer tube 5C defines as a bearing in the slot 26 for the operative member I.

This pin 38 also serves as a fixed support for one end of the spring 2 which spring is held by pressure against the pin 30 and thereby enabled to move the operative member I away from closed circuit position on release of the trigger member 3 from the retaining slot IB.

The stem or rod I is threaded to receive the metal screw 29 which simultaneously holds the forked switch jaws 2B in alignment with the contact plate I5, and also holds a turn of one end of a flexible conducting wire 32, the other end of which is held in firm contact with the con ductor rod 25 by the nut 21. The electric circuit is closed by pressing on the knob indicated at 2IA in dotted lines thereby moving the member I downwards to 2I to enable the jaws of the switch member 20 to engage the plate 23.

The operative member I is provided with a spring 2 normally urging it into open circuit position, i. e. upwards in Fig. 2, and is further provided with a Wedge-shaped lug 22 which acts upon the edge if the trigger member 3 when the operative member I is depressed, forcing the trigger member 3 to engage the slot IB in the side of the operative member I and thereby setting the device in closed circuit position.

To close the electric circuit, the knob at 2Ia is pressed manually moving rod I inwardly. It is held in position, by the trigger slot mechanism, which is moved into closed circuit position by the wedge-shaped lug 22 acting upon the edge of said trigger member 3.

When set, the device is in short circuit, 1. e. the ferrule I1 is in direct electrical contact with the plate I8 and, when screwed into an electric fuse or plug socket the effect will be that of shorting the socket contacts in the usual manner.

The action of the device upon overload is as follows: The diameter and metal content of the conductor wire or rod 25 is designated to heat up and expand in length at a certain amperage.

The nut 24 is adjusted to put a predetermined tension on the rod or wire 25 to pull the movable element of the clamp 5 toward plate 5 with a force that sets up sufiicient friction upon the upper and lower surfaces of the trigger member 3 to hold it in the slot IB against the pressure of the spring I.

At the instant of an overload, the rod or wire 25 expands and releases the tension on the nut holding down the movable clamp member 5, thereby releasing the trigger member 3 to the urging of the spring 4 which pushes the trigger member 3 out of engagement with the slot IB in the operative member I thereby releasing and instantaneously moving it by the pressure of spring 2, thus opening switch 20-43 and breaking the circuit.

The switch jaws 20 are shown in open circuit position by the dotted lines at 20A in Fig. 2.

Obviously, the movement of the operative member I can be utilized for any desired purpose, such as for opening or closing a relay valve or toggle switch, etc, and can be reset as often as required.

While a certain preferred embodiment of the 1 present invention has been illustrated and described herein, it is to be understood that the invention is not limited thereby, but is susceptible of changes in form and detail within the scope of the appended claims.

I claim:

1. An automatic control device including, in combination, an escape member disposed in a housing and having a lug defining a slope and a recess defining an abutment, a spring urging said escape member in the direction of operation, a

biased trigger member disposed transversely of said escape member and adapted to engage said slope and said recess to move and retain said escape member in operative position, wedging means adapted to frictionally engage and hold said trigger member in cocked position and including at least one movable element in parallel alignment with said trigger member and an expansible member operatively connected thereto and connected to a first external contact, said expansible member being responsive to the flow of a current therethrough, thereby to ease the pressure of said wedging means on said trigger and release said escape member for operation by said spring, a sliding contact connected to said expansible element and supported by said escape member and movable therewith and a stationary contact connected to a second external contact and having engagement with said sliding contact in the operative position of said escape member.

2. An automatic control device including, in combination, an escape member disposed in a housing and having a lug defining a slope and a recess defining an abutment, a spring urging said escape member in the direction of operation, a biased trigger member disposed transversely of said escape member and adapted to engage said slope and said recess to move and retain said escape member in operative position, wedging means adapted to frictionally engage and hold said trigger member in cocked position and including at least one movable element in parallel alignment with said trigger member and an expansible member operatively connected thereto and connected to a first external contact, said expansible member being responsive to the flow of a current therethrough, thereby to ease the pressure of said wedging means on said trigger and release said escape member for operation by said spring, a sliding contact connected to said expansible element and supported by said escape member and movable therewith and a stationary contact connected to a second external contact and having engagement with said sliding con tact in the operative position of said escape member, said wedging means including pressure adjusting means connected with said movable element and said expansible member, whereby the pressure of said wedging means on said trigger member may be adjusted.

3. An automatic circuit interrupting mechanism enclosed in a housing and controlled by an expansible member, including the combination of an escape member carrying a movable contact, a stationary contact disposed in said housing for engagement by said movable contact, a trigger member adapted to engage said escape member and extending transversely thereof, wedging means having frictional engagement with said trigger member, said wedging means including a movable element having a friction surface in engagement with said trigger member and said expansible member, and said expansible member being secured at one end to said movable element and fastened at the other end to a contact on said housing, the connection between said movable element and said expansible member ineluding a member extending through said movable element and adjustable to control the pressure of said movable element on said trigger.

LUIS BESCOCCA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,899,915 Matthews Feb. 28, 1933 2,041,000 King May 19, 1936 FOREIGN PATENTS Number Country Date 91,711 Switzerland Apr. 1, 1922 258,553 Italy June 15, 1927 383,105 Germany Oct. 10, 1923 

